Kansai Research Center, Forestry and Forest Products Research Institute, Kyoto 612-0855, Japan.
Field response to several attractants of adults of Trogossita japonica, a predator of the Japanese pine sawyer Monochamus alternatus Hope (Coleoptera: Cerambycidae), the vector of pine wilt disease, was investigated by capture with traps. For the first study, alpha-pinene, beta-pinene, (-)beta-pinene, ethanol and distilled water were used as attractants. T. japonica was strongly attracted to alpha-pinene and (-)beta-pinene. Only a few beetles were captured with traps using beta-pinene and ethanol and no beetles were attracted to distilled water. In the second study, the effect of ethanol in combination with alpha-pinene or (-)beta-pinene was investigated. alpha-pinene, (-)beta-pinene, ethanol, distilled water, alpha-pinene with ethanol, and (-)beta-pinene with ethanol were used as attractants. T. japonica was markedly attracted to alpha-pinene with ethanol but it responded to (-)beta-pinene with ethanol only to the same degree as alpha-pinene or (-)beta-pinene by themselves. Only a few beetles were captured with traps using only ethanol and distilled water. These results indicate that T. japonica orientates to the volatiles of pine logs, especially alpha-pinene with ethanol and this enables it to behave as a predator of bark and wood inhabiting insects in pine. Two predatory clerid beetles, Stigmatium pilosellum (Gorham) and Thanassimus substriatus (Gebler) were also often captured with traps using alpha-pinene with ethanol and (-)beta-pinene with ethanol.